project_telephony/lib/main.dart

import 'dart:async';
import 'package:call_log/call_log.dart';
import 'package:flutter/material.dart';
import 'package:flutter_background_service/flutter_background_service.dart';
import 'package:telephony/telephony.dart';

onBackgroundMessage(SmsMessage message) {
  debugPrint("onBackgroundMessage called");
}

Future<void> main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await initializeService();
  runApp(const MyApp());
}

Future<void> initializeService() async {
  final service = FlutterBackgroundService();
  await service.configure(
    androidConfiguration: AndroidConfiguration(
      onStart: onStart,
      autoStart: true,
      isForegroundMode: true,
    ),
    iosConfiguration: IosConfiguration(
      autoStart: true,
      onForeground: onStart,
      onBackground: onIosBackground,
    ),
  );
}

void onIosBackground() {
  WidgetsFlutterBinding.ensureInitialized();
  print('FLUTTER BACKGROUND FETCH');
}

void onStart() {
  int flag = 0;
  String? phoneNum,callState;
  WidgetsFlutterBinding.ensureInitialized();

  Timer.periodic(const Duration(seconds: 1), (timer) async {
    CallState state = await Telephony.instance.callState;
    callState=state.name;
    print(callState!+"$flag");
    if (callState == "IDLE") {
      if (flag != 0) {
        flag = 0;
        final Iterable<CallLogEntry> result = await CallLog.query();
        phoneNum = await result.first.number;
        print(phoneNum);
        Phone.telephony.sendSms(to: phoneNum!, message: "hello",isMultipart:true,);
      }
    } else if (callState == "RINGING") {
      flag++;
    } else if (callState == "OFFHOOK") {
      flag++;
    }
  });
}

class Phone{
  static Telephony telephony = Telephony.instance;
}

class MyApp extends StatefulWidget {
  const MyApp({Key? key}) : super(key: key);

  @override
  _MyAppState createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  String _message = "";

  @override
  void initState() {
    super.initState();
    final service = FlutterBackgroundService();
    service.start();
  }

  onMessage(SmsMessage message) async {
    setState(() {
      _message = message.body ?? "Error reading message body.";
    });
  }

  onSendStatus(SendStatus status) {
    setState(() {
      _message = status == SendStatus.SENT ? "sent" : "delivered";
    });
  }

  Future<void> initPlatformState() async {
    final bool? result = await Phone.telephony.requestPhoneAndSmsPermissions;
    if (result != null && result) {
      Phone.telephony.listenIncomingSms(
          onNewMessage: onMessage, onBackgroundMessage: onBackgroundMessage);
    }
    if (!mounted) return;
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: const Text('Plugin example app'),
        ),
        body: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            TextButton(
                onPressed: () async {
                  Phone.telephony.sendSms(to: "10086", message: "1");
                },
                child: const Text('sms')),
          ],
        ),
      ),
    );
  }
}